[PATCH 05/44] FT: wpa_auth_ft rrb fix data length

[michael-dev at fami-braun.de]

From: Michael Braun <michael-dev at fami-braun.de>

The FT RRB hostapd packets have a length field.
For PULL frames, it counts the bytes starting with nonce and up to the last
before pad. For RESP frames, it counts the bytes starting with nonce and up
to the last before pad except for 2 bytes. For PUSH frames, it counts the
bytes starting with nonce and up to including pad.

AES encryption is not affected, as rounding hides the differences.
The packets data_length field is not used, so the differences have no
effect there.

As rounding is done with AES encryption, including pad does not make sense.
Not including the last field before pad does not make sense to me either.

So this patch changes the constants to match the bytes used, thus excluding
pad.
To validate the changes, look at remainder modulo 8 of the sum of the size
constants and the padding sizes.

Signed-off-by: Michael Braun <michael-dev at fami-braun.de>
---
 src/ap/wpa_auth.h | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/ap/wpa_auth.h b/src/ap/wpa_auth.h
index b303324..ded9441 100644
--- a/src/ap/wpa_auth.h
+++ b/src/ap/wpa_auth.h
@@ -42,10 +42,11 @@ struct ft_rrb_frame {
 #define FT_PACKET_R0KH_R1KH_RESP 201
 #define FT_PACKET_R0KH_R1KH_PUSH 202
 
-#define FT_R0KH_R1KH_PULL_DATA_LEN 44
-#define FT_R0KH_R1KH_RESP_DATA_LEN 76
-#define FT_R0KH_R1KH_PUSH_DATA_LEN 88
 #define FT_R0KH_R1KH_PULL_NONCE_LEN 16
+#define FT_R0KH_R1KH_PULL_DATA_LEN (FT_R0KH_R1KH_PULL_NONCE_LEN + \
+				    WPA_PMK_NAME_LEN + FT_R1KH_ID_LEN + \
+				    ETH_ALEN)
+#define FT_R0KH_R1KH_PULL_PAD_LEN (8 - FT_R0KH_R1KH_PULL_DATA_LEN % 8)
 
 struct ft_r0kh_r1kh_pull_frame {
 	u8 frame_type; /* RSN_REMOTE_FRAME_TYPE_FT_RRB */
@@ -57,10 +58,14 @@ struct ft_r0kh_r1kh_pull_frame {
 	u8 pmk_r0_name[WPA_PMK_NAME_LEN];
 	u8 r1kh_id[FT_R1KH_ID_LEN];
 	u8 s1kh_id[ETH_ALEN];
-	u8 pad[4]; /* 8-octet boundary for AES key wrap */
+	u8 pad[FT_R0KH_R1KH_PULL_PAD_LEN]; /* 8-octet boundary for AES block */
 	u8 key_wrap_extra[8];
 } STRUCT_PACKED;
 
+#define FT_R0KH_R1KH_RESP_DATA_LEN (FT_R0KH_R1KH_PULL_NONCE_LEN + \
+				    FT_R1KH_ID_LEN + ETH_ALEN + PMK_LEN + \
+				    WPA_PMK_NAME_LEN + 2)
+#define FT_R0KH_R1KH_RESP_PAD_LEN (8 - FT_R0KH_R1KH_RESP_DATA_LEN % 8)
 struct ft_r0kh_r1kh_resp_frame {
 	u8 frame_type; /* RSN_REMOTE_FRAME_TYPE_FT_RRB */
 	u8 packet_type; /* FT_PACKET_R0KH_R1KH_RESP */
@@ -73,10 +78,14 @@ struct ft_r0kh_r1kh_resp_frame {
 	u8 pmk_r1[PMK_LEN];
 	u8 pmk_r1_name[WPA_PMK_NAME_LEN];
 	le16 pairwise;
-	u8 pad[2]; /* 8-octet boundary for AES key wrap */
+	u8 pad[FT_R0KH_R1KH_RESP_PAD_LEN]; /* 8-octet boundary for AES block */
 	u8 key_wrap_extra[8];
 } STRUCT_PACKED;
 
+#define FT_R0KH_R1KH_PUSH_DATA_LEN (4 + FT_R1KH_ID_LEN + ETH_ALEN + \
+				    WPA_PMK_NAME_LEN + PMK_LEN + \
+				    WPA_PMK_NAME_LEN + 2)
+#define FT_R0KH_R1KH_PUSH_PAD_LEN (8 - FT_R0KH_R1KH_PUSH_DATA_LEN % 8)
 struct ft_r0kh_r1kh_push_frame {
 	u8 frame_type; /* RSN_REMOTE_FRAME_TYPE_FT_RRB */
 	u8 packet_type; /* FT_PACKET_R0KH_R1KH_PUSH */
@@ -92,7 +101,7 @@ struct ft_r0kh_r1kh_push_frame {
 	u8 pmk_r1[PMK_LEN];
 	u8 pmk_r1_name[WPA_PMK_NAME_LEN];
 	le16 pairwise;
-	u8 pad[6]; /* 8-octet boundary for AES key wrap */
+	u8 pad[FT_R0KH_R1KH_PUSH_PAD_LEN]; /* 8-octet boundary for AES block */
 	u8 key_wrap_extra[8];
 } STRUCT_PACKED;
 
-- 
1.9.1